The first sign of the disease was a red flush of the face, easily mistaken for the bright red cheeks that many men exhibit after exposure to the frosty air of a cold winter’s day. But fever followed, slight at first, but rising, ever rising. Bleeding did not help, nor garlic, nor any of the various potions, poultices, and tinctures that were tried. Packing the afflicted in tubs of snow and icy water seemed to slow the course of the fever, but did not halt it, those maesters who grappled with the disease soon found. By the second day the victim would begin to shiver violently and complain of being cold, though he might feel burning hot to the touch. On the third day came delirium and bloody sweats. By the fourth day the man was dead…or on the path to recovery, should the fever break. Only one man in four survived the Winter Fever. Not since the Shivers ravaged Westeros during the reign of Jaehaerys I had such a terrible pestilence been seen in the Seven Kingdoms.
The winter which had begun on Maiden's Day, 130 AC - during the Dance of the Dragons - ultimately lasted a full six years, ending in 135 AC. In the aftermath of the war, the Winter Fever struck Westeros - the worst epidemic it had suffered since the Shivers, 70 years before.
The Winter Fever first appeared in the Three Sisters, late in the year 132 AC, where it killed half the population of Sisterton. The survivors believed that it had been brought to their shores by whaling ships from the Port of Ibben, and slaughtered every Ibbenese they could find. The Maesters, however, never confirmed if the disease originated in the dark forests of far away Ib.
The disease then crossed the Bite to White Harbor, where it killed Lord Desmond Manderly. His son Ser Medrick Manderly outlived him by only four days before succumbing to it as well. Ser Medrick was childless, so the lordship passed to his younger brother Torrhen Manderly, who was thus forced to leave the regency council in King's Landing to take up rule of White Harbor.
From Sisterton and White Harbor, the Winter Fever spread southward through the major ports of the east coast: to Gulltown, then Maidenpool, then Duskendale in turn. There were reports around this time that it spread to nearby Braavos as well.
On the third day of 133 AC, the Winter Fever arrived in King's Landing. The first afflicted were those along the riverside, sailors and dockworkers. Before most even realized they were ill, it had already spread throughout the city. When word reached Ser Tyland Lannister, the Hand of the King, he ordered the City Watch to close the city to all entry or exit until the disease ran its course, and to bar the gates of the Red Keep as well. A Pentoshi merchantman was later accused and found guilty of bringing the Winter Fever from Sisterton to King's Landing (though it's unclear if this conviction was true).
By mid-133 AC, the Winter Fever had run its course in King's Landing. Tyland Lannister was one of the last to die from it, even as new cases were tapering off. Tens of thousands were killed, and ultimately almost one fifth of the city's population died, as only about one in four people who caught the disease survived.
Even though the epidemic had subsided in King's Landing, the fever continued in other parts of Westeros throughout late 133 AC. It was noted that the power of the disease grew somewhat less as it passed south, perhaps explaining why it was largely confined to major ports, but in the North it was much more potent, and widespread across large areas. By late 133 the Winter Fever even descended on Barrowton, the other major population center in the North, which was surprising as it was the first time the disease had ever spread so far inland. A wildling chieftain called Sylas the Grim took advantage of this weakness to lead 3,000 wildling raiders south of The Wall, and Cregan Stark had to rally what healthy men he could to stop them. The North remained ravaged by disease and famine for some time.
The following people are known to have died of Winter Fever:
The Vale of Arryn:
- Many in White Harbor and Barrowton.
- Lord Desmond Manderly, in 132 AC.
Ports on the Narrow Sea:
King's Landing and the Crownlands:
- Almost a fifth of the population of King's Landing.
- Ser Tyland Lannister, in 133 AC.
- Queen Alicent Hightower, in 133 AC, who had remained imprisoned since the war ended in 131 AC.
- Two of Queen Jaehaera Targaryen's maids.
- The Commander of the City Watch.
- His successor died nine days later.
- Ser Willis Fell, Lord Commander of the Kingsguard, in 133 AC.
- Lord Leowyn Corbray, in 133 AC.
- His mistress and several of his servants.
- Lord Roland Westerling, in 133 AC.
- Hazel Harte, wife of Lord Velaryon and mother of future queen Daenaera Velaryon.
The following people are known to have recovered from the Winter Fever:
- Grand Maester Munkun
- Lord Manfryd Mooton. Although he technically recovered, it badly damaged the elderly man's health, which many said never truly recovered. He ultimately died only a year later.